I was particularly interested in how the authors measured psychopathy. Here is a relevant excerpt:

Using UK data, we construct a number of corporate psychopathy indicators and link them to the returns that ensue over the next 250 trading days - a period roughly equivalent to one calendar year.

Even if clear guidance exists on how to diagnose psychopathic personality disorder in humans (Hare 1991, 2003), the practical difficulty is that executives will be generally unwilling to participate in time consuming surveys, particularly those that are likely to expose the dark side of their character. We choose to follow a more pragmatic approach and, similarly to Chatterjee and Hambrick (2007), collect information in an unobtrusive way by going through company-related archives and data. Firstly, using automated content analysis we assess to what extent the language in annual report narratives is symptomatic of psychopathy. This is done by counting the frequency of words that are aggressive, characteristic of speakers who are self-absorbed and who have the tendency to assign blame to others. Secondly, we look at likely correlates of managerial integrity. More specifically, we try to identify companies whose auditors have expressed reservations in the Emphasis of Matter section of the annual report and those that have experienced a publicized Financial Reporting Council (FRC) intervention. Thirdly, we consider a measure that derives from the observation that psychopaths require stronger external stimuli to experience emotions and, therefore, have the tendency to take high risks. We assume that excessive exposure in a corporation will result in a high degree of idiosyncratic risk. This type of risk, which is entirely company-specific and unrelated to the broader economy, is measured in our empirical inquiry. Lastly, we construct a variable to capture the reluctance of a company to donate to charitable causes.

Our empirical investigation documents a negative association between the presence of managerial psychopathic traits and future return on common equity.